Cutting Tools Made of High Speed Steel

High-speed steel (HSS), used primarily as a cutting material (for cutting tools), is a high-alloy tool steel. HSS is also used in the manufacturing of tools such as threading taps and drill bits, as it is well suited for grinding (e.g. it also permits regrinding of blunt tools).

It allows cutting speeds up to three to four times faster compared to cold working steels, so higher application temperatures can be achieved. This is down to the heat treatment process, as the steel is annealed above 1200°C and then cooled

The hardness of HSS comes from its basic structure, which consists mainly of iron and carbon. In addition, alloy additions of more than 5 percent make HSS a high-alloy steel

Advantages of High Speed Steel (HSS)

• Application temperatures excess of 600°C

• High cutting speed

• High strength (high breaking strength) Good abrasion resistance in the production process

• Tools can be resharpened

• Relatively cheap

HSS - Co5 or HSS - Co8 indicates the percentage of cobalt content. The higher the cobalt content, the harder the tool steel. The cobalt content increases the heat-resistant hardness and allows for better cutting of difficult-to-cut materials.Co5 contains 4.8 - 5% cobalt and Co8 contains 7.8 - 8% cobalt. However, as hardness increases, toughness decreases.

In addition to cutting speed and the resulting application temperature, wear also affects tool life. This can be balanced by coatings that allow for higher cutting speeds

HSS tools can be coated with a variety of coatings to enhance wear resistance and, most importantly, improve tool life